Re: [bug] __nf_ct_refresh_acct(): WARNING: at lib/list_debug.c:30 __list_add+0x7d/0xad()

Patrick McHardy wrote:

Eric Dumazet wrote:

quoted

IPS_CONFIRMED_BIT is set under nf_conntrack_lock (in 
__nf_conntrack_confirm()),
we probably want to add a synchronisation under ct->lock as well,
or __nf_ct_refresh_acct() could set ct->timeout.expires to extra_jiffies,
while a different cpu could confirm the conntrack.

Before the conntrack is confirmed, it is exclusively handled by a
single CPU. I agree that we need to make sure the IPS_CONFIRMED_BIT
is visible before we add the conntrack to the hash table since the
lookup is lockless, but simply moving the set_bit before the hash
insertion should be fine I think.

A slightly changed version which moves hash insertion to the end
and adds a comment about ordering. This make sure the timer is
actually running before the conntrack can be found be other CPUs.